Operation
30
DK58113 Developer Kit User Manual
2
2.4
Drive Protection and Control
Signals
2.4.1
I
2
t Current Foldback Protection
The MC58113 uses current feedback to implement I
2
t current limiting. This feature protects the on-card amplifier by
controlling its ability to operate above specific selected continuous current ratings.
When the current loop is enabled and the I
2
t energy limit is exceeded, the MC58113 will automatically fold back the
phase currents to a user programmable continuous current limit value. Alternatively, the MC58113 can be configured
to fault and disable the output stage when the I
2
t energy limit is exceeded. See the
Magellan Motion Control IC User Guide
for details.
2.4.1.1
I
2
t
Limits
To safely operate the on-card DK58113 amplifier it is necessary to specify I
2
t limits.
For use with motors that have current and energy limits lower than those specified above, it may be useful to reduce
these parameters.
If a remote amplifier (via the J12 connector) is used the value of these settings will likely change. If an Atlas amplifier
is used these parameters do not need to be specified.
Parameter
Value &
Units
Comments
Brushless DC motor: Foldback
Continuous Current Limit
5.0 A
This value should be entered to ensure the on-card amplifier
does not operate above the maximum safe current output.
Brushless DC motor: Foldback Total
Energy Limit
125 A
2
sec
This value should be entered to ensure the on-card amplifier
does not operate above the maximum safe current output.
DC Brush motor: Foldback
Continuous DC Current Limit
5.0 A
This value should be entered to ensure the on-card amplifier
does not operate above the maximum safe current output.
DC Brush motor: Foldback Total
Energy Limit
125 A
2
sec
This value should be entered to ensure the on-card amplifier
does not operate above the maximum safe current output.
Step motor: Foldback Continuous
Current Limit
5.0 A
This value should be entered to ensure the on-card amplifier
does not operate above the maximum safe current output.
Step motor: Foldback Maximum
Energy Limit
125 A
2
sec
This value should be entered to ensure the on-card amplifier
does not operate above the maximum safe current output.
These limits are designed to be safe for operation of the DK58113’s on-card amplifier when cooled with a 110
CFM (or higher) fan and with an ambient room temperature of 25 degrees C. For use without a fan, or in higher
ambient temperature environments, these values should be lowered.
If special heatsinking is used the DK58113 card is capable of driving motors at 7 amps continuously or higher, in
which case these limits can be increased. Contact PMD for details.
It is the responsibility of the user to set the Foldback Continuous Current and Foldback Energy Limit parameters
to values that are safe for the DK58113 heat sinking scheme and motor setup being used.
